Method for retarding water evaporation



United States Patent Oflice 3,518,047 Patented June 30, 1970 3,518,047METHOD FOR RETARDING WATER EVAPORATION Richard W. Alsgaard, Midland,Mich., assignor to Dow Corning Corporation, Midland, Mich., acorporation of Michigan No Drawing. Filed Aug. 15, 1968, Ser. No.752,791 Int. Cl. B01j 1/18 US. Cl. 21-605 51 Claims ABSTRACT OF THEDISCLOSURE A process for retarding water evaporation in which an aqueoussurface is treated with an organosilicon compound. An example of theorganosilicon compound is CmHgqSiHg.

The present invention relates to a process for retarding evaporationfrom aqueous surfaces and to an aqueous body in which the surfacecarries an evaporation retarder.

The conservation of water is very important throughout the world. Theincreasing population and industry have created an urgent need forconserving as much water as possible. In hot and dry climates largeamounts of water are lost through evaporation. One such area is thesouthwestern section of the United States of America. Large sums ofmoney have been and are now being spent to satisfy the water needs. Onemethod being diligently investigated is the desalination of ocean waterto provide additional fresh water to meet the growing demands.Desalination is a very expensive means of btaining fresh water whencompared to the natural sources of fresh water. After going through theexpensive desalination process for obtaining fresh water, much of theWater is lost to evaporation which adds to the total cost of the wateras Well as to cause the requirements for fresh Water to increase.

One solution to this problem was to find a way to retard the evaporationof the water and thus save the water already available and obtain asmuch utility from as little water as possible. One means of retardingwater evaporation is to disperse on the water surface a fatty alcohol asis shown by Russell G. Dressler in The Suspension Process for ReservoirEvaporation Control," Industrial and Engineering Chemistry, vol. 56, No.7, July 1964, pages 36 and 39. This method is a reasonable approach,since the fatty alcohol does retard the evaporation of water to acertain extent, however, it has one failure in that the fatty alcohol isconsumed by microorganisms such as bacteria. A search for a bettersolution to the problem of conservation of water is continuing.

It is thus an object of the present invention to provide a method forretarding evaporation of water from aqueous bodies. Still another objectis to provide a water evaporation retarder which is not as biodegradableas the fatty alcohols.

The present invention relates to a method for retarding waterevaporation comprising dispersing on an aqueous surface, which is incontact with an atmosphere, an organosilicon compound selected from thegroup consisting of (CH3): (C1192 in which n has a value of from 12 to45 inclusive, p has a value of from 10 to 14 inclusive, x has an averagevalue of from 30 to 40 inclusive and each R and R is selected from thegroup consisting of methyl radicals and phenyl radicals.

The surface of an aqueous body is treated such that the definedorganosilicon compounds are dispersed on the surface. Any suitable meansof causing the aqueous surface to have a dispersion of the definedorganosilicon compound can be used. The means for dispersing the definedorganosilicon compounds can include, for example, spraying either afinely divided solid or liquid on the aqueous surface, forming anorganic solvent solution of the defined organosilicon compounds whereinthe organic solvent is a volatile organic solvent and then spraying,pouring or dispersing by pipes on the aqueous surface, applying anaqueous dispersion on the aqueous surface of the aqueous body, and thelike.

The aqeous body can be a stationary or changing body. If the aqueousbody is a changing aqueous body wherein the additions and removals ofparts of the aqueous body are from the surface of the aqueous body,additional organosilicon compound should be added as required tomaintain the desired amount on the surface. In some cases this wouldinvolve continuous addition of organosilicon compound. Thus, theevaporation of water can be retarded by dispersing and maintaining anevaporation retardant film of the organosilicon compound on the aqueoussurface. Where the removals from a changing aqueous body do not effectthe surface, additions are usually not required.

The organosilicon compounds useful as evaporation retardants in thepresent invention include those having long chain alkyl radicalsattached to the silicon atom through silicon-carbon bonds. It iscompletely unexpected that these organosilicon compounds would retardthe evaporation of water. What is even more unexpected is that not allorganosilicon compounds having long cha n alkyl radicals will retardwater evaporation.

The organosilicon compounds useful as evaporation retardants includethose having a formula (C H )SiH wherein n has a value of from 12 to 45,examples include CmHggSiHa, C12H25SiH3, C1 H SiH C H SiH3,

w s'z i a zo u a 21 43 3 ao m s C H S1H and C H SiH those having aformula i (0 Hm-i) SiH2 wherein n is defined above, examples include,

l CszHuSiHa, and C45Hg SiH2 those having a formula wherein n is definedabove, examples include, 7 wherein n is defined above, examples include(01192 (CH3)2 (CHa)2 (CH3): OCHzCHa OCHzCH:

CmHnSlH, C 1 H2pSiH, C i7Ha5SlH, C mHmSlH C rzHzaSi-O CHzCHz-N, CmHnSi-OCHzCHr-N (C1192 1 92 HM 5 OCHzCHz OCHzCHz CzzH4 SiH, CzsH SiH andC45HmSiH; OCHzCHa OCHzOHs those of a formula C20H41Si-O CHzCHz-N,ozsHnSl-O CHzCHz-N I H OCHzCHz OCHzCHz n Znl'O )2 and 1 1 CHzCHz whereinn is defined above and each R and R is a methyl C4 H91SiO CHzOHz-Nradical or a phenyl radical, examples include OCHZOHZ (?H3)2 C (em): 9CH3): 0 those of the formula 12H25 (OeCH3), H ZB CH3. laHiUSl -O CH3 (CH )Si 3 E wherein n is defined above, examples include Cz1H4aSiO--( JCH3, C45H91SiO- CHa C H Si[OCH CH N(CI-I CH -HCl] ma 0 H3 (a) (3113 E CH Si[OCH CH N(CH CH H011 C H Si[OCH CH N(CH CH -HCl] 0 211 5100011301112 $10- CH3, CmHwSlO- CH3 41 2 2 2 3 2 H H H c rn slrocn cn mcn crrH01 6 5 0 5 U 5 d (3113 (3118 f (0591 O C H Si[OCH CH N(CH CH -HCl] C4HmSiO-C CH3, C1aH2 S|iOC CH3, C12H25SiO-C CH3 those of the formula H5 0H 0 Com o H 0 Camp g a (CH SiO(SiO),Si(CH C14H2nSiO- CH3, cun sio CH3 I3 (c H )2 o Hm 0 l" 5 A] LB wherein p 1s 10 to 14 inclusive and x has anaverage cm and value of 30 to 40 inclusive, examples include those of aformula 0 "H25 C IDE W wmnsio(sromsucrms, a)a )ao a)a |iH2n+i)Si(O A}CHa)2 H3 H3 wherein n is defined above, examples include 011m 203 hu KQa, a)s )au a)a 00115 0 0.11,, o

| [(g g Ha Ha C12Hz5Si(0 CHM, CuHzrSF-(O CHa)z CHEW CHE" CgHa 0 05115 0l g I g 03 M K M, a)a )a4 a)a C1aHa7Si-(O (EH02, C2oHnSi(O CH3): H H

3 S H 0 0 H o o H 00011 d C H s a ((i CH 4' 010B a 2s 5s 1 sh 46 91 1(ofiah )a5 a)a, 3)a (SiO)ao a)a those of a formula (0.11): (31211200141120 CuHn CH (CnHmfiDsiOCHa 50 a)a 0( )zu( )2o a)a and a)s )a1 a)a H3H; CH3

wherein n 1s defined above, examples mclude those of a formula al-Is): uah 1 5): 01102 CnHzsSiOCHa, CuHzgSiOCHa, CmHwSiOCHz, CmHaaSiOCHa (CH3),(CH8): (0.115 (06115): (0.115), cnmfisioona, CHIHGSSlOCHfl andcibnusioom wherein defined aboveexamplesinclude a): 02 02 H3): (CH (CHthose of a formula C1zH2SiOSi0H, CuHzqSi-O-SiOH, O1 H;, SiO-SiOH 0(CH3)? (CH3): (CH3)! (CHM (CH3)! (CH0: g os ogo w CmHnSi-O-SiOH, Cz|H5SiOSiOH, C4rH5gSiO-SiOH wherein n is defined above, examples include andH H CisHoiSi-O-SiOH, OlCHzCHCHzSiOH and OflHflSlOH M K M H Ze K OI Thepreferred organosilicon compounds are those of 0 the following formulaeCmHa KO CHQJa, CaaHo1 (O J CHz)a and CMHMSMO CHm a)2 s CH3 CH3 those ofa formula (CnHm-i-fiSiH, (C HhflOiHZ, (CnH2n+ )SiH ClCHzHCHziOH OCHaCH:R o (CqHg): H3 (0.13am) Si-O CHzCHz-N conHznmslio ll CH3, (cum niio 011Q GHgCHs iv where n is 18 to 45 inclusive and R and R are defined above.

The organosilicon compounds can be applied to the aqueous body as singlespecies or as mixtures of any two or more of the above definedorganosilicon compounds.

The organosilicon compounds can be applied in any amount which iseffective in retarding water evaporation. The evaporation of water canbe retarded by spreading a thin film of the organosilicon compound onthe aqueous surface. The film can be continuous or discontinuousdepending on the desired results. It is preferred, however, that atleast 0.001 g. be applied per square inch of aqueous surface. Usuallynot more than 0.010 g. per square inch of aqueous surface is applied foreconomical reasons since any greater amount does not substantiallyreduce the evaporation rate. Amounts greater than 0.010 g. per squareinch of aqueous surface, of course, can be used, such as up to 1.0 g.per square inch of aqueous surface. The particular amount oforganosilicon compound used will depend upon the conditions of theatmosphere and aqueous body and the particular results desired.Conditions such as temperature and movement of the atmosphere and/oraqueous body will be influential factors in the amount used.

The process of this invention is useful in retarding evaporation where adrying atmosphere is in contact with the surface of an aqueous body. Theaqueous body can be in an open tank, a ditch, a trough, a pan, a kettle,a bowl, a barrel, a dish or a closed vessel with a drying atmospherepassing through it, or it can be a pond, a lake or a reservoir.

By varying the amount of organosilicon compound applied to the surface,the evaporation rate can be controlled. By controlling the evaporationrate, specific cooling effects can be accomplished which are due to theevaporation process. Thus, the present process can be used to controlthe temperature of an aqueous body under certain conditions.

The organosilicon compounds of the present invention are particularlyuseful since they are not consumed to any great extent bymicroorganisms. For all practical purposes, the organosilicon compoundscan be considered non-biodegradable. Thus, replacements required by thedisappearance of the evaporation retarder is very small compared toprior materials used, such as the fatty alcohols.

The evaporation retarders can best be prepared by the following methods.Compounds of the formula can best be prepared by reacting an appropriatea-olefin with HSiCl in the presence of a platinum catalyst, such aschloroplatinic acid. The resulting product has a formula (C H )SiCl This(C H SiCl is then mixed with lithium aluminum hydride to produce n2ri+1) a Compounds of the formula can best be prepared by reacting ana-olefin with H(CH )'SiCl in the presence of a platinum catalyst, suchas chloroplatinic acid. The resulting product has a formula (C H2 +1)The is then mixed with lithium aluminum hydride to produce n 2n+1) a) 2-Compounds of the formula (C H )(CH SiH can best be prepared by reactingan a-olefin with H(CH SiCl in the presence of a platinum catalyst, suchas chloro platinic acid. The resulting product has a formula (C H (CHSiCl. The (C H (CH SiCl is then mixed with lithium aluminum hydride toproduce n 2n+1) 3)2 Compounds of the formula 0 (0.11am) :Si0(J on,

can best be prepared by reacting an a-olefin with HRRSiCl in thepresence of a platinum catalyst, such as chloroplatinic acid. A compoundof the formula R n Zn-I-UiCI is obtained. This R (CUHQMOISiCI is thenmixed with sodium acetate to produce 0 (CnH2n'H)% CH Another method ofpreparing compounds of the formula 0 nfizuflio clia is to react thecorresponding chlorosilane with acetic anhydride.

Compounds of the formula CBH5 C") (CnHzim) Si-(O C CH3)2 can best beprepared by reacting H(C H )SiCl with an a-olefin in the presence of aplatinum catalyst, such as coloroplatinic acid. A compound of theformula (C,,H2..+l)SiClz is obtained. The

(Jam

(CnHmu-DSiCh is then mixed with sodium acetate to produce C6115 0 (CnHtn.+i)S i-(O 4% CH3):

Another method of preparing compounds of the formula e s O nH2n-H)S i (OAl CH3)2 is to react the corresponding chlorosilane with aceticanhydride.

Compounds of the formula (CnH2n+i)SiO CH3 can best be prepared byreacting an a-olefin with H(C H SiCl in the presence of a platinumcatalyst,

such as chloroplatinic acid. The resulting product has a formula (C,,H2n+1)SiCl This (C nHzm-QSiCI is then mixed with methanol to produceThe best method of preparing (3-chloro-3-methylpropyl)dimethylsilanol isto mix (3-chloro-2-methylpropyl)dimethy1chlorosilane with sodiumbicarbonate in the absence of water. The mixture is filtered to removethe sodium chloride which is formed and to recover the (3-chloro-2-methylpropyl)dimethylsilanol. Carbon dioxide leaves the mixtureas a gas. The (3-chloro-2-methylpropyl) dimethylchlorosilane can beprepared by the method described in The Addition of Silicon Hydrides toOlefinic Double Bonds, Part V. The Addition to Allyl and MethallylChlorides, Journal of the American Chemical Society,"volum'e 82, July20, 1960, pages 3601 to 3604,'

by John W. Ryan, Gerald K. Menzie and John L. Speier.

Compounds of the formula V (CHa)2 (CH9);

( nH2n+i)Si-OSiOH can best be prepared by reacting one mole of ana-olefin with one mole of [H(CH Si] O in the presence of a platinumcatalyst, such as chloroplatinic acid. The resulting product is amono-adduct of the formula 1102 Hah (CnHmm) Si-O-SiH This mono-adductcan then be hydrolyzed by using water and a palladium on charcoalcatalyst. The resulting product has a formula ..H2..+1)siosi0rr and canbe recovered by distillation.

Compounds of the formula n 2n+l) Si-O CH2CH2-N 0 CH2CH2 can best beprepared by the method described in US. Pat. No. 3,118,921. In themethod of U.S. Pat. No. 3,118,921, an alkoxysilane is reacted withtriethanolamine. The alkoxysilane used to obtain the o CHZCHI (0.11am)Si-O CH2CH2-N O CHzCHz of the present invention has a formula n 2n+1)*)3 which can be prepared by reacting the appropriate u-olefin withHSi(OR*) in the presence of a platinum catalyst, such as chloroplatinicacid. The OR is preferably methoxy or ethoxy. The alkoxysilane is mixedwith triethanolamine and then heated whereby methanol or ethanol areevolved from the mixture and the product is formed.

Compounds of the formula (C I-E Si [OCH CH N(CH CH 2 HCl] 3 can best beprepared by the method described in US. Pat. No. 2,814,572. Thechlorosilanes of the formula n 2n-l-1) 3 are reacted with (CH CH NCH CHOH. The

is prepared as described above.

Dirnethylphenylsilanol is a known compound and can be prepared by themethod described in Example 1 of US. Pat. No. 3,099,640.

with the appropriate a-olefin in the presence of a platinum catalystsuch as chloroplatinic acid according to the method as described inGreat Britain patent specification No. 1,041,870.

The following examples are illustrative only and should not be construedas limiting the invention which is proper ly delineated in the appendedclaims.

EXAMPLE 1 A liter flask was charged with 252 g. of octadecene-l andheated to C. To the heated octadecene-l was added 110 g. ofdimethylmonochlorosilane and 0.15 cc. of chloroplatinic acid. Thereaction was exothermic and the temperature rose to 128 C. and was heldthere for onehalf hour. The excess dimethylmonochlorosilane was removedby heating the mixture. The product showed no silicon-bonded hydrogenatoms when an infrared spectra was obtained. The product obtained was isa'z) 3)2 in a yield of 44.5 g.

A vapor phase chromatogram was run on the product and a small amount ofoctadecene-l was still unreacted. The product was then heated to C. and50 g. of dimethylmonochlorosilane and 0.10 cc. of chloroplatinic acidwas added. The reaction mixture was refluxed. The excessdimethylmonochlorosilane, which was 45 g. was removed.

A 250 ml. flask was charged with cc. of acetic acid and 16.4 g. ofsodium acetate. The mixture was stirred until the sodium acetatedissolved. At room temperature, 41.6 g. of the (C H (CH SiCl was addedto the sodium acetate solution, resulting in a two-phase system. Themixture was then stirred and a white solution resulted. The mixture wasstirred for 6 hours. The resulting product was 0 1aHa7)(CHs)2SiO( il CH3in a yield of 44.5 g.

A 4 weight percent solution of octadecyldimethylacetoxysilane in diethylether was prepared. On the surface of 100 g. of tap water in a 250 ml.stainless steel cup, 0.2 g. of the octadecyldimethylacetoxysilanesolution was placed. The amount of octadecyldimethylacetoxysilane on thesurface was 0.008 g. The surface area of the water exposed to theatmosphere was 5.9 square inches. Thus, the amount ofoctadecyldimethylacetoxysilane was 0.00136 g. per square inch of aqueoussurface. The resulting assembly was placed in a controlled atmosphere of65% relative humidity and 68 F. The weight of the cup, water andoctadecyldimethylacetoxysilane solution was initially determined andthen observed at time intervals of 1 day, 2 days, 5 days and 7 days. Acontrol cup was also placed in the controlled atmosphere. The controlwas prepared as above, but without the octadecyldimethylacetoxysilanesolution. A 4 weight percent diethyl ether solution ofoctadecyldimethylsilanol was used in place of theoctadecyldirnethylacetoxysilane. This was used as a comparison to showthe unique properties of the e compounds.

Percent water loss after- Percent 1 day 2 days 5 days 7 days c rfti i(1) Control 7. 3 14. 7 35. 47. 2

CH3 0 (2) 01811378 i-O 10113 1. 3 2. 3 8. 2 1S. 2 61. 4

( His CH (3) OlSHMiOH 7. 1 10. 5 37. 4 50. 1 G. 1

EXAMPLE 2. 150 C. for one hour. The resulting product was stripped (A) Aflask was charged with 242 g. of a mixture of a-olefins. The a-olefinmixture contained a-olefins having from to carbon atoms per molecule andthe average molecular weight of the mixture was 242. To the mixture ofa-olefins 159.3 g. of (C H )HSiC1 was added, the mixture being under anitrogen atmosphere. The resulting mixture was heated to C. and 0.1 ml.of chloroplatinic acid was added. The temperature of the reactionmixture was maintained between 120 C. and C. for one hour. The resultingmixture was then stripped to C. at about 1 mm. of Hg pressure to removeany unreacted materials. The product obtained was where q was 15 to 20ina yield of 273.1 g.

'In a 100 ml. flask, 8.6 g. of sodium acetate was dissolved in 55 cc. ofacetic acid and then 24 g. of the prepared above, was added. A whiteprecipitate formed immediately. The mixture was stirred for 7 hours. Athree phase system resulted. The top phase of the three phase system wasthe product phase. The bottom liquid phase was acetic acid and sodiumacetate and the bottom solid phase was sodium chloride. The mixture wasseparated by filtering, decanting and the product phase was stripped toremove any impurities. The product was obtained in a yield of 10.7 g.and was where q was 15 to 20 inclusive. The melting point was 24 (B) A500 ml. flask was charged with 266 g. of the (X- olefin mixture asdescribed in (A) above, and was then heated to 125 C. To the heatedmixture, 100 ml. of trichlorosilane and 0.25 ml. of chloroplatinic acidwere added. The mixture was maintained between 100 C. to

at less than 1 mm. of Hg up to a pot temperature of C. The resultingproduct was obtained in a yield of 297 g. and was (C H )SiCl where q was15 to 20 inclusive.

In a 300 ml. flask, 25.8 g. of sodium acetate was added and thendissolved in 150 ml. of acetic acid. The solution was stirred and then47.9 g. of the (C H )SiCl prepared above, was added. The resultingmixture was stirred for 3 hours and then the product was separated asdescribed above in (A). The product was obtained in a yield of 20.8 g.and was where q was 15 to 20 inclusive. The product had a melting pointof 47 C.

(C) A flask was charged with 700 g. of decene-l, 300 g. of

H I (CHa)3SiO(CHsSiO) a5Si(CHa):

and 0.35 ml. of chloroplatinic acid. The mixture was cloudy at thebeginning of the reaction, but became clear. The mixture showed someunreacted SiH and 35 g. of decene-l was added. Most of the SiH thendisappeared. The mixture was stripped to 140 C. at 3 mm. of Hg. Theproduct remaining was CmHzl (CHa)aSiO CHsSiO) MSKCHa):

having a viscosity of 1105 cs. at 25 C.

(D) Ten weight percent solutions of the above products of (A), (B) and(C) in diethyl ether were prepared. The diethyl ether solutions werethen tested as described in Example 1 above, except 0.02 g. of each ofthe products was used instead of 0.008 g.

The results below are the weight percentages of water lost in a givenperiod under the test conditions.

Percent water loss after- Percent savings over control 1 day 2 days 5days 7 days 00H: H (2) l52fl 3l-ll 1-(O 0 CH3) 2 ll (3) it-20113141 S KC zOa (4) (CHs)aSiO(CHaS1O)-z5Si(CHa):

EXAMPLE 3 (A) A flask was charged with 45.0 g. of octadecene-l and twodrops of chloroplatinic acid. The resulting mixture was stirred andheated to 125 C., then 28.0 g. of monoethylmonophenylmonochlorosilanewas s l o W l y added. The resulting mixture was stirred and thenallowed to cool. The product obtained was C H SiCl (311.7

in a yield of 72 g.

To 36 g. of the octadecylmethylphenylchlorosilane was added 150 g. of asolution of 5 weight percent sodium acetate in acetic acid. This mixturewas heated at 50 C. for minutes. A white precipitate of sodium chlorideformed and was removed by filtration. The remaining mixture was allowedto stand and it separated into two phases. The top phase was the productphase. The top phase was decanted and then stripped at 175 C. for onehour under reduced pressure. The product obtained was CiaHa1Si-O C CH:

(B) A mixture of 28 g. of a-octadene and 5 drops of a one weight percentsolution of platinum, as chloroplatinic acid, in isopropanol was warmedto 100 C. and then 21.8 g. of H(C H SiCl was dropped into it. Thereaction was slow and the resulting mixture was maintained at about 100C. for one day. After one day, 10 g. of additional a-octadene and 5additional drops of the platinum solution was added. The resultingmixture was heated to 150 C. and then 5 more drops of the platinumsolution was added. The resulting mixture was heated until only a traceof silicon-bonded hydrogen could be detected. The product was C gH3q(CH5)2SlC1 and was recovered by removing the volatiles by distillation atreduced pressure.

(C) A portion of the C H (C H SiCl was dissolved in acetone and excesssodium acetate was added. The resulting mixture was agitated and thenthe sodium chloride and remaining sodium acetate were filtered from thesolution. The solution was distilled to remove the acetone. The productwas and had a refractive index, n of 1.5104.

(D) Another portion of the C1 H37(C H5)2SlCl was mixed with methanol andallowed to stand for 64 hours. The remaining methanol was stripped fromthe reaction mixture and C1gH37(C -;H5)2siOCH3 was obtained which had arefractive index, n of 1.5151.

(E) The following ingredients were mixed and allowed to stand in asealed container overnight, 10 g. of

12.6 g. of octadene-l and 2 drops of a one weight percent solution ofchloroplatinic acid in isopropanol. The resulting product was recoveredby distillation (ca. 100 C.) and had a formula of (CI-I97 (CHM (3, HzSi-O-S1H In a bottle, 7.6 g. of the (CH3)2 (CH3)2 C 5H37sl0sl.H

dioxane, a catalytic amount of palladium on charcoal and 0.35 g. ofwater was mixed and allowed to stand with occasional mixing. Hydrogengas evolution began as soon as the ingredients were mixed. The solutionwas allowed to stand overnight. The solution was then filtered anddistilled whereby the product of the formula (CHa)2 (CH7):

C1sH37Si-OSlOH was obtained.

(F) Ten weight percent solutions of each of the products of (A), (C),(D) and (E) in diethyl ether were prepared. The diethyl ether solutionswere then tested as described in Example 1 above, except 0.02 g. of eachof the products was used instead of 0.008 g. The control was prepared asdescribed in Example 1 and the following 10 weight percent diethyl ethersolutions of octadecylmethylphenylchlorosilane,octadecyldiphenylisopropoxysilane and (CH3)2 (CH3)? CisHa1SiOSiH wereused as comparisons to show the unique retarding properties of thecompounds of the present method.

The results below are the weight percentages of water lost in a givenperiod under the test conditions.

Percent water loss after- Percent savings 1 day 2 days 5 days 7 dayscoritii l (1) Control 7. 3 l4. 7 35. 0 47. 2

(2) 0151137 S lOC OH; 4. 9 18. 8 29. 4 37. 6H.

C H O (3) 0131137 S iO CH3 G. 7 25. 8 39. 2 16. 9

( lsl-ls Calls (4) C1sHa7S iO CH: 5. 4 12.1 27. 2 40. 7 13. 7

CH CH (5) GisHn S iO-SiOH 4. 5 10. 4 31. 7 44. 1 6. 6

CHa CH;

CsHs

(6) CIEHS7SlCI 12. 5 20. 7 57. 0 74. 0 -5e. a

CuHa

(7) C1aHa7SiOCH(CH3)2 6. 9 15. 5 35. 9 52. 4 11. 0

( MEL) CH CH (8) CisHa7E liO- iH 8. 9 17. 3 44. 9 65. 1 37. 9

CH CH EXAMPLE 4 (A) Sodium bicarbonate was mixed with a smaller amountof (3 chloro-2-methylpropyl)dimethylchlorosilane. Sodium bicarbonate wasadded to the mixture until no further sodium chloride formed. Themixture foamed during the escape of the carbon dioxide. The mixture wasfiltered to remove the sodium chloride and any unreacted sodiumbicarbonate and the remaining clear liquid was(3-chloro-2-methylpropyl)dimethylsilanol.

(B) A mixture of 1.5 g. of LiAlH in tetrahydrofuran was made by slowlyadding the LiAlI-L; to the tetrahydrofuran in a laboratory set up whichwas then closed with a stirrer and dropping funnel. The system waspurged with nitrogen gas. The nitrogen purge was maintained during thereaction. To the tetrahydrofuran-LiAlH; mixture, 14.7 g. of CmHgqSlClgwas added slowly from the dropping funnel. Some tetrahydrofuran was usedto rinse the dropping funnnel near the end of the addition of the C HSiCl The reaction flask was cooled with a 'water bath as it became warmduring the addition. After completion of the addition of the C H siClthe flask was allowed to cool. The resulting mixture was then filteredto remove some solid particles and then water was slowly added to themixture causing warming of the mixture and an evolution of hydrogen. Twophases were present and the bottom phase was washed three times withdiethyl ether and the extracts were combined with the top phase, theproduct phase. The product phase was washed three times with water. Thewater was discarded and the ether solution was dried over calciumsulfate. The calcium sulfate was filtered from the solution and theether was evaporated. The remaining product was C H SiH in a 80% yield.a e

(C) A mixture of 9.5 g. of H(CH SiCl and 25.3 g. of octadecene-l wasplaced in a bottle and 3 drops of a one weight percent platinum aschloroplatinic acid in isopropanol was added. The resulting mixture wasplaced in a 110 C. oven overnight and then allowed to stand for twoweeks. The mixture was then distilled and was obtained.

A solution of 2.07 g. of the octadecyldimethylchlorosilane intetrahydrofuran was prepared. To a mixture of 0.65 g. of LiAlH intetrahydrofuran, the octadecyldimethylchlorosilane was added. After theevolution of gas stopped, the mixture was filtered and the filtrate wasallowed to stand over the weekend in a hood to evaporate the solvent.The product was (D) Mixed 11.5 g. of H(CH )SiCl 23.3 g. of octadecene-land 2 drops of one weight percent platinum as 14 chloroplatinic acid inisopropanol in a two ounce bottle. The bottle was capped and placed in aC. oven overnight. The resulting mixture was distilled and was obtainedas the product.

Dissolved 3.5 g. of the octadecylmethyldichlorosilane intetrahydrofuran. Added 0.2 g. of LiAlH to tetrahydrofuran and then addedthe octadecylmethyldichlorosilane solution to it. After the evolution ofgas stopped, the mixture was filtered and the solvent evaporated fromthe filtrate. The product was a white solid of the formula (E) Tenweight percent of the following in diethyl ether were prepared.

described in Example 1 above, except 0.02 g. of each of the products wasused instead of 0.008 g. The control was prepared as described inExample 1.

The results below are the weight percentages of water lost in a givenperiod under the test conditions.

Percent water loss after--- Percent 35? 1 day 2 days 5 days 7 dayscontrol (1) Control 7. 3 14. 7 35. 0 47. 2

CH5 CH (2) C1CH2HCH2iOH 4. 0 8. 0 19. 0 26. 5 43. 9

(3) C1sHa7SiH: 3. 0 4. 5 7. 5 10. 5 77. 8

CHa (4) CXSHU lH 4. 5 8. 5 l9. 5 31. 5 33. 3

(5) CnHnSlHz 4. 0 7. 5 16. 0 26. 0 44. 9

(6) CxaH37Si[OCHzCHzNQCHzCHQaHCHs 6. 5 13. 0 30. 5 39. 0 l7. 4

O CHzCH:

(7) C18Ha1SiO CHzCHz-N 6. 5 14. 0 34. 5 43. 0 8. 9

0 CHzCHz CH: (8) CeHsiOH 6. 5 14. 0 33. 0 42. 0 11. 0

15 EXAMPLE The evaporation of water from a storage tank is retarded whenany one of the organosilicon compounds defined in the table of Example 4substantially covers the aqueous surface.

EXAMPLE 6 (A) A mixture of 19.6 g. tetradecene-l, 13.6 g. HSiCl and 2drops of a one weight percent platinum, as chloroplatinic acid inisopropanol was placed in a bottle and sealed. This mixture was placedin a 120 C. oven overnight. The mixture was then distilled and C14H2SlCl3 Was obtained.

Mixed 0.25 g. of LiAlH in tetrahydrofuran and dissolved 2.66 g. of C HSiCl in tetrahydrofuran. Slowly added thesilane solution to the LiAlHmixture with stir-' ring. After the foaming stopped, the mixture wasfiltered and the tetrahydrofuran was allowed to evaporate. The remainingresidue had two phases, the solid phase was dissolved in water and theorganic portion was dissolved in diethyl ether. The ether and waterphases were separated and the water phase was washed twice with ether.The ether solutions were combined and the ether allowed to evaporate.The resulting product was C H SiH (B) A mixture of 19.6 g. oftetradecene-l, 9.4 g. of H(CH SiCl and 3 drops of a solution of a oneweight percent platinum as chloroplatinic acid in isopropanol was placedin a small bottle and then allowed to stand in a 120 C. oven overnight.The resulting mixture was distilled and the product collected was (CHa):

CuHznSiCl To a mixture of 0.2 g. of LiAlH in tetrahydrofuran, 5.8 g. ofthe tetradecyldimethylchlorosilane in tetrahydrofuran was added. Afterthe evolution of gas stopped the mixture was filtered and thetetrahydrofuran was evaporated, leaving CuHzcSiH as the product (C) Asolution of mixed alkyltrichlorosilanes having alkyl groups ranging fromC H to C l-I in tetrahydrofuran was mixed with LiAlH The reactionmixture was filtered to remove any excess LiAlH and LiCl-A1Cl and thenthe solvent was evaporated. The alkyltrichlorosilane was prepared bymixing a mixture of ot-olefins having 20 to 42 carbon atoms with HSiClin the presence of chloroplatinic acid. The alkylsilanes obtained were amixture having the formula (C I-I )SiH where n was 20 to 42.

(D) Ten weight percent solutions of the products of (A), (B) and (C) indiethyl ether were prepared. The diethyl ether solutions were thentested as described in Example 1 above, except 0.02 g. of each of theproducts were used instead of 0.008 g. The control was prepared asdescribed in Example 1.

The results below are the weight percentages of water lost in a givenperiod under the test conditions.

Percent water loss after 1 6 EXAMPLE 7 The diethyl ether solution ofC1gH37SlI'I3 as described in Example 4 was used in an extended test. Theatmosphere and testing were the same as described in Example 1. Thefollowing results were obtained:

Percent water loss after- 14 days 21 days 28 days (1) Control 74. 2 1002) C H SiH 24. 5 39. 0 57. 0

EXAMPLE 8 When any one of the following compounds are dispersed on thesurface of a water reservoir by spraying in an amount of 0.01 g. of thecompound per square inch of water surface, the evaporation of the wateris retarded.

(CH3)aSiO (SiO )z4Si(CHs)a (1) CH3 (C H2) usiHa (s) a mixture of 30parts by weight CuHasSiHa C111! 30 parts by weight C12H25S iH2 CH2 40parts by weight C H S AH (1H3 (t) a mixture of CH3 20 parts by weightCH3CH2)nS iO-("JCHa CH3 0 10 parts by weight CH2.(CH2)11S iOl CH3 70parts by weight CH3(CH2)11SiO-C CH3 (u) a mixture of CH3 CH3 50 parts byweight C12H25SiO-SiOH CH3 CH:

O CHzCHz 50 parts by weight C45H9iSi-0 CH2CH2-N (v) a mixture of 0H: 20parts by weight C45H91S iHz CH3 20 parts by weight C12H25S iH (B111 20parts by weight CzoEnsiH CH; 20 parts by weight CauHalS iHZ CH2 20 partsby weight C25H51S iH2 (w) a mixture of 30 parts by weight C4 Hq1SiOCH3 0I 30 parts by weight O45H1Si(0 91011 e a 30 parts by weight C45H91Sl-(O(011 EXAMPLE 9 When 1.0 g. per square inch of pond surface of CH (CH SiHis sprayed on the surface of a pond, the evaporation of the water fromthe pond is reduced.

EXAMPLE When 22.1 g. of CH (CH SiH is evenly dispersed on the surface ofa cylindrical tank having a diameter of 20 feet containing an aqueoussolution, the evaporation of the water is retarded and the cooling ofthe aqueous solution due to evaporation is less.

persed on the surface of a pond in an amount of 0.1 g. per square inch,the amount of water lost by evaporation is reduced.

a) Ol CH3(CH2)11S1(O :3 011 (b) CH3(CH2)Si[OCHzCH2N(CH2CH3)2-HC1]2CHs(CH2) Si O-l CH8 onucmmsro-b CH;

(e) CHa(CHz)11Si[O CH CH2N(CHzCHa) 2410.];

That which is claimed is:

1. A method for retarding water evaporation comprising dispersing on anaqueous surface, which is in contact with an atmosphere, anorganosilicon compound selected from the group consisting of,

n has a value of from 12 to 45 inclusive,

p has a value of from 10 to 14 inclusive,

x has an average value of from 30 to 40 inclusive and each R and R isselected from the group consisting of methyl radicals and phenylradicals.

2. The method according to claim 1 in which the amount of organosiliconcompound per square inch of aqueous surface is at least 0.001 gram.

3. The method according to claim 1 in which the organosilicon compoundsubstantially covers the aqueous surface.

4. The method according to claim I]. in which a continuous film isdispersed on the aqueous surface.

5. The method according to claim 1 in which a thin film of theorganosilicon compound is spread on the aqueous surface.

6. The method according to claim 1 in which the amount of organosiliconcompound per square inch of aqueous surface is from 0.001 to 1.0inclusive grams.

7. The method according to claim 1 in which the organosilicon compoundis CH2 (IT/H3): ClCHztHCHzSiOH 8. The method according to claim 1 inwhich the organosilicon compound is (C H (CH SiOH.

9. The method according to claim 1 in which the evaporation of the wateris retarded by dispersing and maintaining an evaporation retardant filmof the organosilicon compound on the aqueous surface.

10. The method according to claim 9 in which the amount of organosiliconcompound per square inch of aqueous surface is maintained within thelimits of 0.001 to 1.0 grams.

11. The method according to claim 1 which the organosilicon compound isin an organic solvent for the organosilicon compound.

12. The method according to claim 111 in which the organic solvent is avolatile organic solvent.

13. The method according to claim 1 in which the organosilicon compoundhas a formula 14. The method according to claim 13 in which n has avalue of from 15 to 20 inclusive.

15. The method according to claim 1 in which the organosilicon compoundhas a formula (CnH2n+1)Si(O CHa)s 16. The method according to claim 15in which n has a value of from 15 to 20 inclusive.

17. The method according to claim 1 in which the organosilicon compoundhas a formula 0 CHzCHa n 2n-H)SlO CHzCHz-N O CHzCHz 18. The methodaccording to claim I17 in which n is 18. 19. The method according toclaim 1 in which the organosilicon compound has a formula s)2 (CHM(C..I-Iz,.+1)Si0SiOH 20. The method according to claim 19 in which n is18. 21. The method according to claim 1 in which the organosiliconcompound has a formula (C H )Si[OCH CH N(CH CH -HCl] 22. The methodaccording to claim 21 in which n has a value of from 18 to 45 inclusive.

23. The method according to claim 21 in which n is 18. 24. The methodaccording to claim 1 in which the organosilicon compound has a formula nZn-l-1)SiH2 25. The method according to claim 24 in which n has a valueof from 18 to 45 inclusive.

26. The method according to claim 25 in which n is 18.

27. The method according to claim 1 in which the organosilicon compoundhas a formula 28. The method according to claim 27 in which n has avalue of from 1 8 to 45 inclusive.

29. The method according to claim 28 in which n is 18.

20 30. The method according to claim 1 in which the organosiliconcompound is C H2 +i (CHmSiO s10) XSKCH 31. The method according to claim30 in which p is 10.

32. The method according to claim 31 in which x is 35.

33. The method according to claim 1 in which the organosilicon compoundhas a formula 34. The method according to claim 33 in which n is 14.

35. The method according to claim 33 in which n has a value of from 18to 48 inclusive.

36. The method according to claim 35 in which n is 18.

37. The method according to claim 1 in which the organosilicon compoundhas a formula .(C H )SiH 38. The method according to claim 37 in which nis 14.

39. The method according to claim 37 in which n has a value of from 18to 45 inclusive.

40. The method according to claim 39 in which n has a value of from 20to 42 inclusive.

41. The method ccording to claim 39 in which n is 18.

42. The method according to claim 1 in which the organosilicon compoundhas a formula 43. The method according to claim 42 in which both R and Rare methyl.

44. The method according to claim 43 in which n: has a value of from 18to 45 inclusive.

45. The method according to claim 44 in which n is 18.

46. The method according to claim 42 in which both R and R are phenyl.

47. The method according to claim 46 in which n has a value of from 18to 45 inclusive.

48. The method according to claim 47 in which n is 18.

49. The method according to claim 42 in which R is methyl and R isphenyl.

50. The method according to claim 49 in which n has a value of from 18to 45 inclusive.

51. The method according to claim 50 in which n is 18.

References Cited UNITED STATES PATENTS 2,640,063 5/1953 Kohl 2160.5 XR2,797,138 6/1957 Veatch et al. 2160.5 2,797,139 6/ 1957 Veatch 2160.53,095,263 6/ 1963 Eckert et al. 21-60.5 3,146,060 8/1964 Canevari 2160.53,431,064 3/ 1969 Fox 21-60.5 3,450,488 6/ 1969 Dressler 21-60.5

MORRIS O. WOLK, Primary Examiner B. S. RICHMAN, Assistant Examiner U.S.Cl. X.R. 252384

